Plate rapping mechanism



April 1945. w. D. YERRICK- ETIAL I PLATE RAPPING MECHANISM Filed April 6, 1943 2 Sheets-Sheet 1 n IIIIIIIIIIIIII'I'I'IIIL INVENTORS .ZZ YZrndC y 1056/42 Wat/Ins arromvgr Patented Apr. 3, 1945 PLATE RAPPING MECHANISM William D. Yerrick and Joseph Waitkus, Wellsville, N. i6, assignors to The Air Preheater Corporation, New York, N. Y.

Application April 6, 1943, 'Serial No. 481,96d

2 Claims. ((31. 257-1) The present invention relates to heat exchange apparatus and particularly to improvements in mechanism for cleaning soot or other deposits from the metallic heat exchange plates of such apparatus.

The invention is specifically concerned with rapping mechanism to vibrate the plates in a rotary regenerative air preheater so as to shake deposits from their surfaces. Apparatus of this general type is disclosed in the Herbeck patent, 2,122,176, issued June '28, 1938. The improved apparatus of the present invention contemplates rapping or vibrating the plates in each compartment of a preheater rotor as the compartments pass a station where the actuating devices for the rapping mechanism are located.

The invention will be best understood upon reference to the following detailed description of and illustrative embodiment thereof when read in conjunction with the accompanying drawings in which:

Figure 1 is a fragmentary horizontal sectional view on the line l-l in Fig. 2 through a rotary heat exchanger and shows several of the rotor compartments with rapping mechanism associated therewithin accordance with the present invention;

Figure 2 is a partial elevational view of a rotary heat exchanger with some parts shown in section and illustrates the rapping mechanism in elevation;

Figure 3 is a view on an enlarged scale of a portion of the mechanism shown in Figs. 1 and 2;

Figure 4 is a sectional view on the line 4-4 in Figure 3;

Figure 5 is an enlarged view of a part of the apparatus; and

Figure 6 is a sectional view on the line 6-6 in Figure 3.

In the drawings the numeral i designates the stationary housing of a rotary regenerative air preheater of the type described in Ljungstrom Patent 1,652,025, issued December 6, 1927. Within the stationary housing ID is mounted a cylindrical rotor ll rotatively driven about the axis l2 and divided by radial partitions 13 into a plurality of sector-shaped compartments I 4, each of which contains heat transfer surface in the form of a plurality of corrugated metallic plates I5. In operation the movement of the rotor I I by the drive mechanism It (Fig. 2) brings the plates l into a gas passage in which they absorb heat from hot boiler gases or the like and upon being further rotated into the air passage they impart the heat to the air.

The metallic heat transfer plates l5 are closely positioned adjacent each other providing relatively narrow passages for the flow of gases and air. As a consequence soot and other deposits accumulate upon the surfaces of the plates l5 after the preheater has been in operation for some time. One of the methods considered most effective for maintaining such heating surfaces clean is to rap or shake the deposits from the surfaces, and one type of mechanism for this purpose is disclosed in the above mentioned Herbeck patent- In carrying out the present invention, each compartment 14 has mounted therein a pair of rods 20 guided for reciprocation above the plates l5 in diaphragm I! that subdivide each sector shaped compartment I4 in the rotor shell H. Each pair of bars 20 supports a series of rapping plates 2| (Figure 5) each hanging downwardly therefrom into the space between adjacent heat exchange plates l5 as appears in Figure 2. The plates 2| are held in fixed position on the rods 20 by stop washers 24 so that if a vibratory movement is imparted to the bars 20 to effect a slight reciprocating movement thereof the plates 2| will strike against the heat transfer plates l5 between which they depend and impart the vibratory or rapping movement thereto. Springs 22 return the bars 20 to their positions of rest as limited by stops 24.

The vibratory movement is efiected upon alinement of each rod 20 with a pneumatic hammer designated as a whole by the numeral which when a rod 28 alines therewith travels with the rotor H during a small part of its movement. The pneumatic hammer is of conventional construction and connected by a hose 3| to a source of compressed air and provided with a vibratory plunger 32. The plunger 32 has a tapered tail piece 39 which in certain positions of the hammer 30 facilitates the engagement of the head 3! on a rod 20 with the plunger by allowing the head 37 as it moves in a circular path to ride up on and be pressed back by the taper of the tail piece 39. As may be seen in Figs. 3 and 4 the hammer 30 is mounted on a carriage 33 having guide rollers 34 riding on short arcuate tracks 35 attached to the outside of the preheater housing l0 along the longitudinal edges of an arcuate opening 36 in housing l0 through which the inner end of the hammer projects for alinement with the enlarged hardened head 3! on a rod 20. As shown, the rotor carries lugs 38 for engaging the arm 40 of a bell crank latch 4| pivoted at 42 on the carriage 33. Upon engagement of the arm 40 by a lug 38 When the rotor has turned to aline a bar 20 with the hammer plunger 32, the carriage is carried around with the rotor through the distance provided for by the lengths of the arcuate slots 36 and the tracks 35. As carriage 33 moves with rotor II the arcuate opening 36 is maintained closed to prevent escape of gas by a sliding door 50 (Figs. 6, 7) moving in guideways 5| formed in the bracket on which the tracks 35 are formed. During this time air is supplied through hose 3| so that the vibrations of the plunger 32 of the pneumatic hammer 30 are imparted to the rod 20 and thence by means of the plates 2| carried thereby tothe heat transfer plates I5 in the rotor compartment. At the end of the predetermined travelof the carriage 33 and hammer 30 with the rotor I la roller 43 carried by the other arm 44 of the latch 41 rides up on a cam 45 mounted on the inner wall surface of the stationary housing 10 disengaging the arm 40 of the latch from the lug 33 on the rotor so that the latter continues its movement unimpeded. The hammer 30 and carriage 33 then remains stationary in the position to which they have been moved by the rotor. 'To become operatively engaged with the other rod 20 in each compartment I 4, or with a rod in the following compartment if only one is provided for each compartment, the carriage and hammer are returned to their starting point by hand so that a second lug 38 may engage latch 4| to restart the cycle. It is obvious, however, that suitable automatic return mechanism might be provided.

The shank of the pneumatic hammer 30 is provided with an adjustable collar 46 engageable with the boss 4! on carriage 33 (Figs. 3, 4) to determine the extent to which the hammer projects into the housing. This affords regulation of the hammer blow imparted to a rod 20 by varying the normal clearance between the outer end of the rod and the striking end of the plunger 32 when in its position of rest so as to utilize during the time the rod is contacted by plunger 32 a greater or lesser part of the reclprocatory movement of which the plunger is capable. The operator presses against the handle of the pneumatic hammer to hold it against outer movement and jarring from the carriage the movement of the hammer on its carriage with the rotor being easily followed because such rotors turn at the slow rate of 2 to 5 R. P. M.

Although illustrative embodiments of the invention have been shown and described'in detail herein it is to be understood that there are many changes and variations that may be made Without departing from the invention and therefore it is desired and intended to include all such changes and variations within the scope of the appended claims.

Whatwe claim is:

1. In an air preheater or the like having a stationary housing enclosing a rotor formed with a compartment carrying spaced heat transfer plates for contact by gases entraining soot or the like, at least one reciprocably mounted bar extending radially of the rotor opposite the plates in each compartment with one end projecting 'from the rotor toward said housing, and means carried by said bars and extending into the spaces between said plates for engagement with the latter to shake soot therefrom upon reciprocation of said bar; a pneumatic hammer having a vibratory member disposed within said housing and adapted to impart a vibratory movement to said bar upon operative alinement of the end of said bar with said member; a carriage guided on the housing opposite the rotor for permitting its movement with the latter and carrying said pneumatic hammer; and means associated with said rotor and carriage for coupling them so the rotor moves the pneumatic hammer along with said bar upon alinement of the latter therewith.

2. In an air preheater or the like having a stationary housing enclosing a rotor formed with a compartment carrying spaced heat transfer plates for contact by gases entraining soot or the like, at least one reciprocably mounted bar extending radially of the rotor opposite the plates in each compartment with one end projecting from the rotor toward said housing, and means carried by said bars and extending into the spaces between said plates for engagement with the latter to shake soot therefrom upon reciprocation of said bar; a pneumatic hammer having a vibratory member disposed withinsaid housing and adapted to impart a vibratory movement to said bar upon operative alinement of the end of said bar with said member; a carriage guided on the housing opposite the rotor for permitting its movement with the latter and carrying said pneumatic hammer; means associated with said rotor and carriage for coupling them so the rotor moves the pneumatic hammer along with said bar upon alinement of the latter therewith; and means for uncoupling said rotor and carriage upon a predetermined movement of the latter 'with the rotor.

WILLIAM D. YERRICK. JOSEPH WAITKUS. 

